AMD Radeon R9 Nano: false modesty

The most unusual GPU Fiji card based, Radeon R9 Nano, has a TDP of just 175 watts and small enough to be installed in the case Mini-ITX, at the same time it also promises performance on par with Radeon R9 Fury. How did they manage to collect these advantages in one device?

In general, AMD have planned to release four devices based on the graphic processor Fiji – the largest and productive GPU of the company of the now existing. Today we will study custom product called Radeon R9 Nano.

Radeon R9 Fury X is an extremely large GPU, which has almost exhausted the possibilities of a production line of 28 nm at the Taiwanese TSMC on the size of the crystal. But the main innovation, thanks to which Fiji has taken its place in the history of graphics processors, – a memory of HBM type (High-Bandwidth Memory), wired with the GPU on a common silicon substrate. HBM allowed overcoming the limitation of bandwidth characteristic of GDDR5 memory, thanks to the wide 4096-bit wire working at a relatively low frequency of 500 MHz (equivalent to 1 GHz, taking into account the data on the basis of DDR).

But there is also another important effect: since all of the lines of the wire memory are in the substrate, GPU with RAM chip occupy a modest area on the circuit board of the accelerator. The reviews of Radeon R9 Fury and Fury X tell about a quite compact reference PCB, which is especially contrasted with the massive radiator of R9 Fury cooling. If there were no task to withdraw 275 watts of heat from the GPU, then based on Fiji could have been created an extremely fast graphics card, suitable even for computer with form factor Micro-ITX. And here it is!

In formal specifications Radeon R9 Nano if similar to the Radeon R9 Fury X. Both accelerators are equipped with a fully unlocked GPU Fiji, only the maximum frequency of the processor in the R9 Nano is 50 MHz lower than of R9 Fury X. At the same time, TDP of two models differs as much as by 100 watts: 175 watts for Nano and 275 watts for Fury X. How AMD managed to achieve this?

Here a number of factors combined. Firstly, the relatively small difference in GPU frequency between R9 Nano and R9 Fury X is made by a great cost in terms of energy consumption than it might seem at first sight – for the simple reason that for higher clock speeds require more high voltage power supply, and chip power is proportional to the square of the voltage. Secondly, for R9 Nano are selected the highest quality Fiji chips, having the lowest current leakage. Thirdly, and most importantly, 1 GHz for R9 Nano is the maximum available frequency of GPU, and under real load it can fluctuate in the range of 300 to 1000 MHz.

Thus, TDP R9 Nano has no mystery. But now raises the question: what share of performance Fiji had to sacrifice to ram card in TDP of 175 watts? However, AMD is confident enough in the practical merits of the product, to establish a price of $649 – exactly the same as for Fury X and GeForce GTX 980 Ti. What should we do, these are the faces of the current economic situation.

Radeon R9 Nano is focused on a narrow niche of the market of video cards for systems of Mini-ITX standard, where it is destined to have the fate of the undisputed leader. Until now the most powerful models that appeared in this format were GeForce GTX 970 and Radeon R9 380, and Radeon R9 Nano aspires to the level of performance of GTX 980 and Radeon R9 Fury.